Showing papers in "Reviews in Environmental Science and Bio\/technology in 2013"

A review of the harvesting of micro-algae for biofuel production

Abstract: Many researchers consider efficient harvesting is the major challenge of commercialising micro-algal biofuel. Although micro-algal biomass can be ‘energy rich’, the growth of algae in dilute suspension at around 0.02–0.05 % dry solids poses considerable challenges in achieving a viable energy balance in micro-algal biofuel process operations. Additional challenges of micro-algae harvesting come from the small size of micro-algal cells, the similarity of density of the algal cells to the growth medium, the negative surface charge on the algae and the algal growth rates which require frequent harvesting compared to terrestrial plants. Algae can be harvested by a number of methods; sedimentation, flocculation, flotation, centrifugation and filtration or a combination of any of these. This paper reviews the various methods of harvesting and dewatering micro-algae for the production of biofuel. There appears to be no one method or combination of harvesting methods suited to all micro-algae and harvesting method will have a considerable influence on the design and operation of both upstream and downstream processes in an overall micro-algal biofuel production process.

Temperature effect on microalgae: a crucial factor for outdoor production

Abstract: High rate outdoor production units of microalgae can undergo temperature fluctuations. Seasonal temperature variations as well as more rapid daily fluctuations are liable to modify the growth conditions of microalgae and hence affect production efficiency. The effect of elevated temperatures, above optimal growth temperatures, on growth is seldom reported in literature, but often described as more deleterious than low temperatures. Depending on the species, different strategies are deployed to counteract the effect of above optimal temperatures such as energy re-balancing and cell shrinking. Moreover, long term adaptation of certain species over generation cycles has also been proven efficient to increase optimal temperatures. Physical models coupled to biological kinetics are able to predict the evolution of temperature in the growth media and its effect on the growth rate, highlighting the downstream drastic economic and environmental impacts. Regarding the relative elasticity of microalgae towards temperature issues, cell mortality can depend on species or adapted species and in certain cases can be attenuated. These elements can complement existing models and help visualize the effective impacts of temperature on outdoor cultures.

Microbial decolorization and degradation of synthetic dyes: a review

Abstract: The synthesis of dyes and pigments used in textiles and other industries generate the hazardous wastes. A dye is used to impart color to materials of which it becomes an integral part. The waste generated during the process and operation of the dyes commonly found to contain the inorganic and organic contaminant leading to the hazard to ecosystem and biodiversity causing impact on the environment. The amount of azo dyes concentration present in wastewater varied from lower to higher concentration that lead to color dye effluent causing toxicity to biological ecosystem. The physico-chemical treatment does not remove the color and dye compound concentration. The decolorization of the dye takes place either by adsorption on the microbial biomass or biodegradation by the cells. Bioremediation takes place by anaerobic and/or aerobic process. The anaerobic process converts dye in toxic amino compounds which on further treatment with aerobic reaction convert the intermediate into CO2 biomass and inorganics. In the present review the decolorization and degradation of azo dyes by fungi, algae, yeast and bacteria have been cited along with the anaerobic to aerobic treatment processes. The factors affecting decolorization and biodegradation of azo dye compounds such as pH, temperature, dye concentration, effects of CO2 and Nitrogen, agitation, effect of dye structure, electron donor and enzymes involved in microbial decolorization of azo dyes have been discussed. This paper will have the application for the decolorization and degradation of azo dye compound into environmental friendly compounds.

Bio-energy recovery from high-solid organic substrates by dry anaerobic bio-conversion processes: a review.

Abstract: Dry anaerobic bio-conversion (D-AnBioC) of high-solid organic substrates (OS) is considered as a sustainable option for waste management practices in different parts of the world. The basic technology is well implemented, but the improvements are still under way in terms of optimization and pre- and post-treatments of the feed and end-products, respectively. The purpose of this review is mainly to: (1) provide existing knowledge and research advances in D-AnBioC systems to treat high-solid OS; (2) identify major issues involved in bioreactor designing; (3) present factors influencing the bio-conversion efficiency; (4) discuss the microbiology of system operation; (5) provide examples of existing commercial-scale plants; (6) discuss energy and economics requirements. From the detailed literature review, it is clear that the characteristics of OS are the major factors governing the overall process and economics. It shows that not all OS are profitably recycled using D-AnBioC systems. Compared to single-stage continuous systems, batch systems under a multi-stage configuration appears to be economically feasible, however, it must be noted that the available data sets are still inconclusive. Also, limited information is available on green house gas mitigation and restoration of nutrients from the digested residue during post-treatment schemes. A summary at the end presents important research gaps of D-AnBioC system to direct future research.

Photobioreactors for the production of microalgae

Abstract: Microalgae are produced today for human and animal markets, as food-feed and source of active compounds. Microalgae can be also used in wastewater treatment and they has been proposed as biofuels source to reduce global warming problem. Whatever the final application of microalgae its production is based on the same principles as light availability, enough mass and heat transfer and adequate control of culture parameters. In this paper these principals are revised. Moreover, the production must be carried out at adequate scale using photobioreactors. Design of photobioreactor is determined by the final use of biomass and quality required. Different designs today used are revised, including last designs proposed, identifying his characteristics parameters and applications. In addition, the obligation of adequate control strategies is discussed. Finally, the bottlenecks for the scale-up of the different technologies and thus of microalgae production are summarized.

From geochemical background determination to pollution assessment of heavy metals in sediments and soils

Abstract: Establishing geochemical background concentrations to distinguish the natural background from anthropogenic concentrations of heavy metals in sediments and soils is necessary to develop guidelines for environmental legislation. Due to the fact that the background concentrations strongly depend on geological characteristics such as mineral composition, grain size distribution and organic matter content, several normalization methods have been developed. Empirical (geochemical), theoretical (statistical) and integrated methods (combining both empirical and theoretical methods) are the main approaches described in literature for determination of geochemical background concentrations. In this review paper, the different approaches as well as the main normalization methods for heavy metal concentrations in sediments and soils will be discussed. Both geochemical background concentrations and added risk level (maximum permissible addition) should be taken into account for setting up legal threshold limits. Moreover, different approaches to evaluate the pollution status of heavy metals in sediments and soils, from Sediment/Soil Quality Guidelines to quantitative indices (Geo-accumulation Index-Igeo, Enrichment Factor-EF, Pollution Load Index-PLI and Risk assessment Code-RAC) will be presented. Although guidelines to establish whether a sediment or soil is polluted or not are generally only related to total metal concentrations, the available/reactive pool i.e., availability/reactivity of metals should be taken into account for sediment/soil pollution assessment.

Toxicity and bioremediation of pesticides in agricultural soil

Abstract: Pesticides are one of the persistent organic pollutants which are of concern due to their occurrence in various ecosystems. In nature, the pesticide residues are subjected to physical, chemical and biochemical degradation process, but because of its high stability and water solubility, the pesticide residues persist in the environment. Moreover, the prevailing environmental conditions like the soil characteristics also contribute for their persistence. Bioremediation is one of the options for the removal of pesticides from environment. One important uncertainty associated with the implementation of bioremediation is the low bioavailability of some of the pesticides in the heterogeneous subsurface environment. Bioavailability of a compound depends on numerous factors within the cells of microorganism like the transportation of susbstrate across cell membrane, enzymatic reactions, biosurfactant production etc. as well as environment conditions such as pH, temperature, availability of electron acceptor etc. Pesticides like dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), Endosulfan, benzene hexa chloride (BHC), Atrazine etc. are such ubiquitous compounds which persist in soil and sediments due to less bioavailability. The half life of such less bioavailable pesticides ranges from 100 to 200 days. Most of these residues get adsorbed to soil particles and thereby becomes unavailable to microbes. In this review, an attempt has been made to present a brief idea on ‘major limitations in pesticide biodegradation in soil’ highlighting a few studies.

Microbial pectinase: sources, characterization and applications

Abstract: Today pectinases are upcoming industrially important bacterial enzymes. It can be produced by a variety of microorganisms. These enzymes act on pectin, which is the major component of middle lamella in plant cell wall. Pectinolytic enzymes are classified according to their mode of attack on the galacturonan part of the pectin molecules such as protopectinases, esterase’s and depolymerases. As we know that microbial enzymes work depends up on the type of enzymes application, temperature, concentration, and pH and so on, therefore, pectinase enzyme also differentiated according to their physical and chemical factors too. The biochemical structures of pectinases include members of all the major classes and the structure–function relationship, studies of a few available complexes of pectinases with substrate/analogs could be considered as prototypes for related family member and the molecular characterization of pectinolytic enzymes is also well documented. Furthermore, it provides a bird’s eye view of the possible application of these enzymes in commercial sector.

Potential use of polyphenol oxidases (PPO) in the bioremediation of phenolic contaminants containing industrial wastewater

Abstract: The present review emphasizes on the use of Polyphenol oxidase (PPO) enzyme in the bioremediation of phenolic contaminants from industrial wastewater. PPO is a group of enzyme that mainly exists in two forms; tyrosinase (E.C. 1.14.18.1) and laccase (E.C. 1.10.3.1) which are widely distributed among microorganisms, plants and animals. These oxidoreductive enzymes remain effective in a wide range of pH and temperature, particularly if they are immobilized on some carrier or matrices, and they can degrade a wide variety of mono and/or diphenolic compounds. However, high production costs inhibit the widespread use of these enzymes for remediation in industrial scale. Nevertheless, bench studies and field studies have shown enzymatic wastewater treatment to be feasible options for biodegradation of phenols through biological route. Nanomaterials-PPO conjugates have been also applied for removal of phenols which has successfully lower down the drawbacks of enzymatic water treatment. Therefore in this article various approaches and current state of use of PPO in the bioremediation of wastewater, as well as the benefits and disadvantages associated with the use of such enzymes have been overviewed.

Impacts of shrimp farming on the coastal environment of Bangladesh and approach for management

Abstract: The frozen food export sector, next to readymade garments sector, is the second largest export earner of Bangladesh. Shrimp, main item of frozen food, is a major contributor in the national economy of Bangladesh since mid 1980s. Although it provides millions of employment and earns more than US$ 445 million annually, it has been facing a host of challenges. Shrimp farming has been associated with a number of negative environmental and social impacts which hinder the sustainable development of this blooming sector. This paper aim to focus on how the shrimp culture in Bangladesh is affecting the adjacent environment as well as society and management approach for it’s sustain ability by means of reviewing the available scientific literatures. It finds the grave socioeconomic impacts including traditional livelihood displacement, loss of land security, food insecurity, marginalization, rural unemployment, social unrest and conflicts in the wake of shrimp culture development in Bangladesh. Similarly, environmental impacts such as mangrove degradation, loss of biodiversity, sedimentation, saltwater intrusion, and pollution and disease outbreaks are found to be the main obstacles for the development of sustainable shrimp farming. Inappropriate management practices and inadequate plans regarding water quality, seed supply, irrigation facilities and fishery resources are the main reasons for these impacts of shrimp farming. The effective management measures to mitigate the adverse environmental impact of shrimp farming development have now become urgent requirement.

Adsorption thermodynamics to clean up wastewater; critical review

Abstract: The current review paper deals with critical evaluation of the thermodynamic parameters of adsorption equilibrium uptakes of heavy metals, dyes and other organic pollutants from the wastewater using low-cost adsorbents, activated carbon derived from agricultural waste, industrial wastes and other important adsorbent materials. Present review paper focus the spontaneity of adsorption processes when the thermodynamic parameters were assessed with the compensation effects of standard enthalpy change (ΔHo) and standard entropy change (ΔSo) with temperature. This paper also investigates the spontaneity of adsorption on the basis of thermodynamic criteria of spontaneity and the temperature range to predict feasibility of the adsorption processes.

Advances in direct transesterification of microalgal biomass for biodiesel production

Abstract: Microalgae biomass is becoming an interesting raw material to produce biodiesel, where several approaches in the transesterification process have been applied such as different catalysts, different acyl acceptors, incorporation of co-solvents and the different operational conditions. However there are some drawbacks that must be solved before any industrial application could be intended. The main problems are related with the high water content of the biomass (over 80 %) and the several process steps involved in biodiesel production such as: drying, cell disruption, oils extraction, transesterification and biodiesel refining. In comparison to other alternatives, the use of direct transesterification could be a suitable alternative since cell disruption, lipids extraction and transesterification are carried out in one step, with a direct reaction of oil-bearing biomass to biodiesel. This process could be applied even using biomass with high water content, and its efficiency could be improved by the incorporation of promising technologies such as microwave or ultrasonication that can enhance the mass transfer rate between immiscible phases, simultaneously diminishing the reaction time. However, it is still necessary to decrease the costs of these technologies so they can be suitable alternatives in future industrial applications.

Current status of heavy metal contamination in Asia’s rice lands

Abstract: Major contribution (over 90 %) to the world’s rice production is coming from Asia, where metal contamination of agricultural lands is often reported. Thus the present paper reviews the sources and current status of heavy metal contamination of paddy lands in the region. Apart from the natural sources, agrochemicals, wastewater irrigation, sewage sludge application, livestock manures, mining and fly ash etc., could be identified as the key sources of metal contamination in Asia. Accumulation of heavy metals and metalloids (Cd, Zn, Cu, Pb, Cr, Ni, Fe, Zn, Co, Hg and As) in different parts of the rice plant (roots, straw, hull and grain) is reported at varying degrees. Rice grain accumulates the least amount of toxic metals compared to hull, straw and roots. Most importantly, a greater number of investigations confirmed that the metal contents in rice grains are within the permissible limits of Codex recommendations of joint Food and Agriculture Organization/World Health Organization Food Standards Programme and/or food regulations imposed by the respective governments. However, due to the fact that rice is a main route of human exposure to heavy metals, appropriate preventive and remedial measures should be enforced in the areas with potential risk of metal contamination.

Organic matter–microorganism–plant in soil bioremediation: a synergic approach

Abstract: Bioremediation is a natural process, which relies on bacteria, fungi, and plants to degrade, break down, transform, and/or essentially remove contaminants, ensuring the conservation of the ecosystem biophysical properties. Since microorganisms are the former agents for the degradation of organic contaminants in soil, the application of organic matter (such as compost, sewage sludge, etc.), which increases microbial density and also provides nutrients and readily degradable organic matter (bioenhancement–bioaugmentation) can be considered useful to accelerate the contaminant degradation. Moreover, the organic matter addition, by means of the increase of cation exchange capacity, soil porosity and water-holding capacity, enhances the soil health and provides a medium satisfactory for microorganism activity. Plants have been also recently used in soil reclamation strategy both for their ability to uptake, transform, and store the contaminants, and to promote the degradation of organic contaminants by microbes at rhizosphere level. It is widely recognized that plant, through organic materials, nutrients and oxygen supply, produces a rich microenvironment capable of promoting microbial proliferation and activity.

Soil flushing: a review of the origin of efficiency variability

Abstract: Soil flushing using aqueous solutions is employed to solubilise contaminants. As water solubility is the controlling mechanism of dissolution, additives (surfactants, cosolvents, etc.) are used to enhance efficiencies and reduce the treatment time compared to the use of water alone. The use of surfactant alone gives efficiencies of about 80–85 % in laboratory experiments, but the amounts of product to be injected are very important, which does not seem to be economically sustainable. Studies indicate that when soil flushing is applied in the field, efficiency is very variable; it can vary from almost 0 % to almost 100 %. This illustrates the importance of knowledge of the field (soil heterogeneities, type of contamination, etc.). Using only one product (surfactant, cosolvent, cyclodextrin) often gives moderate efficiencies and needs very large amounts of products, with a product:pollutant ratio higher than 100:1. On the other hand, the use of more complex methods involving micro emulsions or several products with polymer injection lead to high efficiencies at first and a product:pollutant ratio that can be lower than 5. The importance of the initial saturation of the non-aqueous phase liquid is highlighted: the higher the initial saturation, the higher the efficiency. For initial saturations lower than 1 %, soil flushing may not be a very efficient technique. This paper provides an overview of recent studies in the area of soil and groundwater remediation, from laboratory columns scale to pilot and real sites. The research has focused on chlorinated solvents as they are extremely difficult to treat.

Cometabolism of trichloroethylene: concepts, limitations and available strategies for sustained biodegradation

Abstract: Due to its toxicity and persistence in the environment, trichloroethylene (TCE) has become a major soil and groundwater contaminant in many countries. A group of aliphatic- and aromatic-degrading bacteria expressing nonspecific oxygenases have been reported to transform TCE through aerobic cometabolism in the presence of primary substrate such as methane, ammonia, propane, phenol, toluene or cumene. This paper reviews the fundamentals and results of TCE cometabolism from laboratory and field studies. The limitations associated with TCE cometabolism including the causes and effects of substrate and/or inducer utilization rate and depletion, enzyme inhibition and inactivation, and cytotoxicity during TCE oxidation among various TCE-degrading bacteria and enzymes are discussed. In addition, the potential strategies e.g. addition of primary substrate/inducer or external energy substrate, use of a two-stage reactor and application of cell immobilization for sustained TCE degradation are highlighted. The review summarizes important information on TCE cometabolism, which is necessary for developing efficient TCE bioremediation approaches.

Bio-catalytic desulfurization of fossil fuels: a mini review

Abstract: For a long time now, the combustion of fossil fuels to give usable energy has led to the release of many types of pollutants into the atmosphere. Of particular interest is sulfur dioxide derived from combustion of diesel and related organic-sulfur containing media. Its presence in the air has resulted in the deterioration of health and depletion in aesthetic quality of materials. As a result, environmental regulations are now put in place to regulate the level of sulfur in different fuel types. To achieve this goal, many techniques have been tested, and bio-catalytic desulfurization is now being considered due to some limitations with conventional hydrodesulfurization approach. This essay discusses various kinds of microbial isolates that are harnessed for this purpose, and the influence of genetic engineering techniques and various factors on the activities of these biocatalysts. With increasing knowledge of microbial ecology, better understanding of biochemical systems, exploration of new conversion pathways and optimization of bioreactor design, enhancement in this approach is expected to bring an increase in its acceptability and improve the prospects of its full commercialization as viable alternative to the conventional hydrodesulfurization of fossil fuels.

Biodiesel fuel from microalgae-promising alternative fuel for the future: a review.

Abstract: The use of organic matter such as vegetable oil to produce biodiesel fuel has been a practical technology for a number of years. However, the search for new technologies and raw materials for biodiesel fuel production has gained increased attention recently because of financial and environmental concerns. Of particular interest are raw materials that are not food-related. Microalgae have gained a great deal of attention as a potential biodiesel raw material because of their high growth rates and ability to accumulate oil, bind carbon dioxide, and remove contaminants from wastewater. This article is a literature review of technologies for biodiesel production from microalgae. The technologies relate to microalgal cultivation, microalgal growth enhancement to simultaneously increase biomass and reduce pollution, the preparation of microalgal biomass for biodiesel production, and biodiesel production itself.

Assessment of river quality models: a review

Abstract: The paper reviews river quality models on the basis of their conceptualization, processes, strengths and limitations. It analyzes advances in basic research and compares river quality models, namely AQUATOX, Branched Lagrangian Transport Model (BLTM), One Dimensional Riverine Hydrodynamic and Water Quality Model (EPD-RIV1), QUAL2Kw, Water Quality Analysis Simulation Program (WASP) and Water Quality for River-Reservoir Systems (WQRRS). All these models are widely used and ‘mechanistic’ in nature except for BLTM which was selected due its vast ‘useage’. In addition, the paper highlights the types of errors which occur during the modelling exercise. The paper also emphasizes on the pivotal role played by water quality models for development and formulation of various river restoration projects worldwide. The present review also suggests broad recommendation for choosing a river quality model.

Production of a major stilbene phytoalexin, resveratrol in peanut (Arachis hypogaea) and peanut products: a mini review

Abstract: As a major stilbene phytoalexin, resveratrol is produced or elicited in several plant species as a part of defense systems protecting plants against diseases. Resveratrol can be present in both the trans- and cis-isomeric forms, and only the trans-form increases the life expectancy and lowers the risk of cardiovascular diseases as the most bioactive form. In addition to the usages for diet and industry, peanut plant (Arachis hypogaea) and peanuts are getting higher attention due to their containment of resveratrol in the kernels and other parts of peanut plant, such as leaves, roots, and peanut shell. Recently, natural resveratrol derived from peanuts has also become a promising nutraceutical agent, promoting human health. Resveratrol has also been detected in peanut products including peanut butters, roasted peanuts, and boiled peanuts. Although, smaller and immature peanuts contain higher levels of resveratrol than mature peanuts, resveratrol in peanuts can also be preserved by cooking or manufacturing processes. Moreover, the amount of resveratrol in peanut plants and peanuts has been found to increase by external stimuli including microbial infection, wounding, UV light irradiation, ultrasonication, yeast extract treatment and by plant stress hormones. In addition, molecular level analysis has confirmed that four resveratrol synthase (RS) genes (RS1, RS2, RS3 and RS4) which catalyze synthesis of resveratrol have been identified in peanuts, and up-regulation of the genes is positively correlated to the increased contents of resveratrol. In this review, we summarize the natural biosynthesis of resveratrol in peanuts and peanut plants, as well as the occurrence of this natural phytoalexin in various peanut products. A brief knowledge on the biosynthetic pathway of resveratrol synthesis has been described. This review also deals on highlighting the effect of various external stimuli (biotic and abiotic stresses) in order to achieve the maximum induction and/or elicitation of resveratrol in peanuts and peanut plants.

Reliable predictive computational toxicology methods for mixture toxicity: toward the development of innovative integrated models for environmental risk assessment

Abstract: A main objective in the field of mixture toxicity is to determine how well combined effects are predictable based on the known effects of mixture constituents. Conducting toxicity tests for all conceivable combinations of chemicals, to understand all mechanisms in the combined toxicity of environmental pollutants, is virtually unfeasible due to cost- and time-consuming procedures. Therefore, predictive tools for mixture toxicity are required to be developed within the applicable range of predictive toxicology. The concept of concentration addition (CA) model is often considered a general method for estimating mixture toxicity at the regulatory level. In the long run, however, the possibility of toxicological synergism between mixture components actually occurs, especially from the no-effect level or non-toxic substances. This is ignored under the CA concept, and needs to be examined and integrated into existing addition models at a scientific level, this paper reviews existing integrated models for estimating the toxicity of complex mixtures in literature. Current approaches to assess mixture toxicity and the need for new research concepts to overcome challenges which recent studies have confronted are discussed, particularly those involved in computational approaches to predict mixture toxicity in an environment risk assessment based on mixture components.

Current views on EDDS use for ex situ washing of potentially toxic metal contaminated soils

Abstract: The paper presents a mini-review on EDDS use for ex situ chemical washing of potentially toxic metal contaminated soil. The attention is focused, initially, on studies aimed at verifying the biodegradability and the toxicity of free EDDS and metal-EDDS complexes. Free EDDS is found to be highly biodegradable. Metal-EDDS complexes, instead, are indicated as having variable biodegradability, but their toxicity is found to be always very low. The results obtained during soil washing treatments are successively reviewed. Removal percentages as high as 80–90 % are indicated as maximum obtained values. The extraction process is initially very fast, and then tends to slow down reaching the final equilibrium in about 1 week or even more. Generally acidic conditions are favourable to enhance the process. The influence of organic matter on process efficiency and the interactions between EDDS and soil minerals are also considered, revealing variable effects of the organic matter presence depending on its characteristics, and highlighting the possibility of iron and aluminium washing off during the remediation treatment.

Reviewing the prospects of Opuntia pears as low cost functional foods

Abstract: Opuntia (prickly pear) is a genus of xerophytes belonging to the Cactaceae family, growing luxuriantly in the arid parts of the world. Recently, the pears of Opuntia have been discovered to contain a plethora of biologically active compounds. Owing to their high nutritional value, in terms of dietary fiber, polyunsaturated fatty acid-rich oil, minerals, protein, and an assortment of other phytochemicals, the pears are gaining popularity as exotic, gourmet diet. Multiple health benefits viz. antioxidant, anti-inflammatory, antidiuretic, hypocholesterolemic, antidiabetic, antiproliferation, immunostimulatory and antiulcerogenic activity have emerged. The review summarizes the nutraceutical aspects of the pears and the possible strategies to minimize their postharvest loss. Rich in functional ingredients, these pears are expected to revolutionize the processed foods industry and solve food scarcity in developing countries. However, no significant attempt has yet been made to benefit from this potential nutritive storehouse. This review is prepared with a vision to bolster its status as a viable food and drug supplement.

Food, pharmaceutical and industrial potential of Carissa genus: an overview

Abstract: Shrubs belonging to Carissa genus (Apocyanaceae family) are potential sources of food, medicine and fuel, yet they are wallowing under obscurity and rarely been exploited. Edibility of the pulpy Carissa fruits is known to only a meagre few. Since antiquity, the stem, root bark, leaves, fruit and seed extracts have been used in folklore medication. Now, the emerging scientific investigations are validating the ethno-medicinal uses of these species. Bioactive compounds which include viz. polyphenolics, flavonoids, flavanones, lignans and sesquiterpenes imparting therapeutic potential to these species have been isolated. In vitro and in vivo studies have shown these species to have antioxidant, analgesic, anti-inflammatory, hypolipidemic, wound healing, antimicroabial, antidiabetic, antiepileptic, anticancer, diuretic, nephrotoxicity amelioration and hepatoprotective activity. This miraculous plant extract has also been effective in the management of veterinary ailments. Apart from the medicinal attributes, this genus also holds promise as a suitable alternative crop for harvesting renewable energy. Micropropagtion is being tried for rapid multiplication of the valuable species. This review summarizes the recent findings for promoting the versatility of this genus.

Pollutant dispersion in the urban environment

Abstract: Flow and pollutant dispersion models are important elements for managing air quality in urban areas, to complement and, sometimes, even substitute monitoring. Developing fast and reliable parameterisations is necessary to improve the spatial and temporal resolutions of current mathematical prediction models. Recently there has been a growing interest in the so-called “neighbourhood scale” models, that offer relatively high spatial and temporal resolutions while keeping the needed computational resources at a minimum. This paper describes experimental and numerical simulations performed to explore the interaction of flow and pollutant dispersion with local building and street geometry. The methods developed may be useful as a way for cities to improve air quality management.

MINOTAURUS: microorganism and enzyme immobilization: novel techniques and approaches for upgraded remediation of underground-, wastewater and soil

Abstract: The European project MINOTAURUS aims to deliver innovative bio-processes to eliminate emerging and classic organic pollutants. These bio-processes are all based on the concept of immobilization of biocatalysts (microorganisms and enzymes) and encompass bioaugmentation, enzyme technology, rhizoremediation with halophytes, and a bioelectrochemical remediation process. The immobilization-based technologies are applied to engineered ex situ and natural systems in situ for the bioremediation of groundwater, wastewater and soil. The selection and application of modern physico-chemical, biological and ecotoxicological monitoring tools combined with a rational understanding of engineering, enzymology and microbial physiology is a pertinent approach to open the black-box of the selected technologies. Reliable process-monitoring constitutes the basis for developing and refining biodegradation kinetics models, which in turn will improve the predictability of performances to be achieved with our technologies. A key strength of MINOTAURUS is the possibility of direct implementation of our technologies at five European reference sites that are confronted with pollutants (two technologies will be tested on-site starting from the first year). We will deliver not only a set of tools, techniques, and processes, which will enhance the ability of our communities to respond to the challenges of organic pollutants but also frameworks for structuring and making evidence-based decisions for the most sustainable and appropriate bioremediation measures. The MINOTAURUS consortium includes fifteen partners from eight European countries. Eight research & education institutions, five SMEs covering the whole chain of our bioremediation approaches (production, and monitoring of biocatalysts, bioremediation and engineering), one large end-user operating wastewater treatment plants and one environmental agency work together with the support of an advisory board mainly consisting of environmental decision-makers.